Various valve constructions and arrangements are known for controlling the flow of fluids such as liquids through associated piping and conduits. In certain applications, it can be desirable to provide for selective fluid communication between one or more of a plurality of individual pipes and another main pipe. This can be accomplished by providing each of the individual pipes with its own respective isolation valve, and then joining the valves together by a suitable T-connection, header, or the like for communication with the main pipe. In some applications where it is desired to prevent reverse flow within the individual pipes, suitable flow check mechanisms can be provided so that fluid flow is only possible in one direction.
Although arrangements of the above description are very commonly employed to permit selective fluid communication between the individual pipes and the main pipe, the drawbacks of such an arrangement will be readily appreciated. Because individual isolation valves are provided for each of the individual pipes, fabrication, installation, and maintenance expenses can be relatively high. Additionally, the amount of space required for this typical arrangement can complicate installation. The expense is further compounded if each of the individual pipes must be provided with a suitable flow check mechanism. In use, it is frequently necessary to operate each of the individual valves when it is desired to alter the fluid communication between individual pipes and the main pipe. Naturally, this detracts from convenient operation of the arrangement, and may even result in some uncertainty as to which of the individual pipes are joined at any given time to the main pipe.
A further consideration which must be made during the design and installation of pipe valving arrangements relates to the service requirements of the system. In many applications, the nature of the fluids being piped and controlled dictate the type of valving that is suitable for use. For example, in facilities which handle and treat sewage and other wastes, or otherwise abrasive and corrosive liquids, the equipment installed must be specially adapted for the rigorous service requirements. Not only does this frequently limit the type of isolation valves which can be suitably employed, but it also can significantly increase the maintenance requirements for the equipment. Naturally, the use of a number of individual valve mechanisms which must each be periodically serviced complicates and increases the cost of effective maintenance.
In some installations, so-called three-way or four-way valves can be used for effecting communication between plurality of individual pipes and a main pipe. While such arrangements desirably reduce the number of individual components in a system, such valves are limited in the selection of desired flow direction.
In view of the above, the introduction of a single multi-position valve unit which can be employed for providing selective communication between a plurality of individual pipes and a main pipe in any combination is particularly desirable. It is particularly advantageous if such a valve unit can be easily installed and maintained, particularly if the unit is suited for use in applications such as sewage handling and treatment in which the control of corrosive and/or abrasive materials is required.